Chaos Resistance is doubled 
Cleansed Thoughts is a notable passive skill that doubles chaos resistance.
Note that if you have negative chaos resistance (due to Kitava's penalties and other items such as OskarmQuality: +20%
Evasion: 130Requires Level 52, 50 Dex(30-40)% increased Global Accuracy Rating
+(40-50) to maximum Life
-(20-10)% to Chaos Resistance
(7-8)% chance to Dodge Spell Hits
Trigger Level 10 Assassin's Mark when you Hit a Rare or Unique Enemy
2% increased Attack Critical Strike Chance per 200 Accuracy RatingLand and sea did not dissuade,
nor did the Kelpie's maw;
the wild beast crossed half the world
to sate his hungry claw.), having Cleansed Thoughts would double chaos resistance towards the negative side (i.e. -10% chaos resistance to -20% chaos resistance).
It is only available by anointing an item (amulet or Blight-specific unique that has the help text: "This item can be anointed by Cassia").